Date: Thu, 14 Jun 2012 12:53:07 -0700 From: Ryan Goodfellow <rgoodfel@eecs.wsu.edu> To: freebsd-current@freebsd.org Subject: Re: DTrace broken on 9.0-Release? Message-ID: <EF688929-B1ED-487F-94CF-F84806FDDC9E@eecs.wsu.edu> In-Reply-To: <5BD5B2B1-7165-4705-8750-50EEBB5E26F2@neville-neil.com> References: <5D6510D5-A8B3-41D9-B175-15FA680AF7F2@eecs.wsu.edu> <20120614115301.1cd0975b@fabiankeil.de> <5BD5B2B1-7165-4705-8750-50EEBB5E26F2@neville-neil.com>
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Hi everyone, and thank you for the very prompt responses. I did indeed compile world with CFLAGS+=-fno-omit-frame-poiner in my make.conf. I will file the PR shortly. Thank You Ryan G On Jun 14, 2012, at 9:00 AM, George Neville-Neil <gnn@neville-neil.com> wrote: > Top post. > > File a PR and assign it to me (gnn) please. > > I'm on vacation until Sunday but I am actively working on DTrace when I'm not > on vacation. > > Best, > Geo > On Jun 14, 2012, at 02:53 , Fabian Keil wrote: > >> Ryan Goodfellow <rgoodfel@eecs.wsu.edu> wrote: >> >>> Today I downloaded and installed FreeBSD 9.0-RELEASE and followed the >>> directions from <http://wiki.freebsd.org/DTrace>; to get DTrace up and >>> running. The output of DTrace instrumenting a simple program, however, >>> is not correct. The program is as follows: >>> >>> // test.cc >>> #include<cstdlib> >>> >>> int main(void) { >>> for(int i = 0; i < 5; i++) { >>> malloc(47); >>> } >>> } >>> >>> then compiling and running DTrace as follows: >>> >>> g++ test.cc -o test >>> >>> dtrace -n 'pid$target::malloc:entry{ }' -c ./test >>> >>> >>> The correct output for this example is something to the tune of: >>> >>> dtrace: description 'pid$target::malloc:entry' matched 2 probes >>> dtrace: pid 95236 has exited >>> CPU ID FUNCTION:NAME >>> 0 188748 malloc:entry >>> 0 188748 malloc:entry >>> 0 188748 malloc:entry >>> 0 188748 malloc:entry >>> 0 188748 malloc:entry >>> >>> (this from a machine with the same code running DTrace) >>> >>> The DTrace session should also make an immediate exit on completion. On >>> FreeBSD I have the following CPU ID FUNCTION:NAME >>> 2 42213 malloc:entry >>> >>> and the execution does either not exit on it's own or hangs, it requires >>> a ctrl-c. >> >> Doesn't work for me either on 10-CURRENT amd64. >> Converting it to C doesn't make a difference, it works if >> one changes the loop to "for (;;)", though. >> >>> I followed the instructions from the FreeBSD site exactly, compiling and >>> installing the custom kernel. I used both clang++ and g++ for >>> compilation with the same result. The system has even completely hung >>> on other attempts. >>> >>> Is DTrace not something that should be relied upon in FreeBSD? I have >>> also tried this on the latest 10-CURRENT build with the same result. >> >> In my opinion the problem with DTrace on FreeBSD is that while it's >> known to be incomplete, there doesn't seem to be documentation >> available about which parts are supposed to work already and which >> aren't. >> >> For example the trivial example program at: >> http://wiki.freebsd.org/DTrace/userland (which works for me) doesn't >> actually use a counting loop, so maybe dtracing your example program >> isn't supposed to work yet and never did on FreeBSD. >> >> Without documentation it's hard to tell. >> >> Fabian >help
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